The present invention relates to a rotatable shaft assembly and, more specifically, to a shaft assembly for use in rotatable valve assemblies such as butterfly valves.
There are numerous apparatuses which employ rotatable shaft assemblies in which provision must be made to prevent blowout of the shaft from the assembly. Such blowout can occur, for example, if the shaft is in an assembly which is subject to high pressures which can act on the shaft to expel it from the assembly. In particular, in the case of rotatable valve assemblies such as ball valves, butterfly valves and the like, it is often times necessary that the shaft or shafts which are attached to the rotatable valve element, e.g. ball, disk, etc., be provided with a means to prevent the shaft from being blown out of the valve body in the event the shaft shears or if the shaft otherwise is freed from the rotatable valve element such as by failure of the attachment means used to secure the shaft to the valve element. Prior art valve assemblies having blowout proof stems or shafts generally suffer from the disadvantage that the shaft is difficult to remove from the assembly should it be necessary to disassemble the valve or to replace the shaft should it fail.